The present invention relates to a copying apparatus comprising a fixed optical system for making a slit exposure and means for moving and scanning a document so as to scan and expose the document as it moves, and also to copy an optical image projected from a separately added option device.
The copying apparatus represented by an electrophotographic copying apparatus has practically been used in many ways for the purpose of copying documents, and almost all of the copying apparata are constructed to obtain a copy of the same size from a sheet-like or book-like document. On the other hand, an apparatus that copies a document that is reduced or enlarged and printed is also known, But such apparatus is permanently assembled as part of a copying apparatus, and, as or in the case using an option or accessory device, use is made of the same optical path as that of the copying apparatus itself or use is made of a part of an optical path of the copying apparatus itself in common. It is a common technique to inseparably assemble a reduction optical system in the copying apparatus itself, but the thus assembled apparatus becomes large and complicated. In the case of adding a detachable optical image projector to the copying apparatus itself as an option device, such apparatus also has various defects. For example, in Japanese Patent Application Publication No. 4,944/67, Japanese Patent Application Publication No. 8,437/69, Japanese Patent Laid-open No. 62,724/76, Japanese Utility Model Laid-open No. 127,827/77, Japanese Patent Laid-open No. 55,647/77 and the like, there is disclosed that the whole image surface of a microfilm image is projected on a document table or a photosensitive member as a still picture by an option device and the projected image is scanned and exposed in the former apparatus by a scanning optical system, while in the latter apparatus the projected image is directly converted into an electrostatic latent image. However, the copying apparatus for copying the whole image surface of a microfilm image simultaneously projected as a still picture is as large as the the apparatus itself and lacks versatility and convenience as compared with the copying apparatus of a document moving, scanning and exposing type which has recently found acceptance. In the former system for projecting the microfilm image on the document table, when an enlarged image is projected by an option device, it is necessary to provide a long optical path, so that the option device becomes disadvantageously large.